This project is designed to develop procedures to control body weight in high risk children and prevent adult obesity. Three studies are proposed. The first study involves the third, fourth and fifth year of follow-up for a group of high risk preadolescent obese children who participated in a randomized clinical trial determining the effects of targeting parent and child or child alone in a behavioral weight control program. The second study assesses the importance of regular exercise and child self-control in a ramdomized prospective three year study on preadolescent obese children. The third study is designed to develop treatment procedures to control development of body weight in high risk young children between six months and two years of age. Parents will be trained to change eating and activity patterns, and to reduce the use of food as a stimulant and reward for child behavior.